Adhesive and thermal interface material on a plurality of dies covered by a lid

Abstract

Provided are a package structure and a method of forming the same. The package structure includes a first die, a second die group, an interposer, an underfill layer, a thermal interface material (TIM), and an adhesive pattern. The first die and the second die group are disposed side by side on the interposer. The underfill layer is disposed between the first die and the second die group. The adhesive pattern at least overlay the underfill layer between the first die and the second die group. The TIM has a bottom surface being in direct contact with the first die, the second die group, and the adhesive pattern. The adhesive pattern separates the underfill layer from the TIM.

What is claimed is: 
     
       1. A method of forming a package structure, comprising:
 bonding a first die and a second die onto an interposer; 
 dispensing an underfill layer between the first die and the second die; 
 forming a first encapsulant to laterally encapsulate the first die, the second die, and the underfill layer; 
 dispensing a thermal interface material (TIM) on the first die, the second die, the underfill layer, and the first encapsulant, wherein the TIM has an edge thickness greater than a center thickness of the TIM; and 
 mounting a lid on the TIM, wherein the TIM has a first concave top surface, the lid conformally covers the first concave top surface of the TIM, and the lid has a second concave top surface corresponding to the first concave top surface. 
 
     
     
       2. The method of  claim 1 , wherein a sidewall of the first encapsulant is substantially aligned with a sidewall of the interposer. 
     
     
       3. The method of  claim 1 , further comprising:
 bonding the interposer onto a circuit substrate; and 
 bonding a passive device onto the circuit substrate. 
 
     
     
       4. The method of  claim 1 , wherein before the dispensing the TIM, the method further comprises:
 forming an adhesive pattern on the underfill layer between the first die and the second die, and the adhesive pattern separates the underfill layer from the TIM. 
 
     
     
       5. The method of  claim 4 , wherein the forming the adhesive pattern comprises:
 selectively dispensing on the underfill layer between the first die and the second die to form a plurality of adhesive layers discretely distributed to each other. 
 
     
     
       6. The method of  claim 5 , wherein each adhesive layer has a bottom surface in direct contact with a top surface of a corresponding portion of the underfill layer. 
     
     
       7. The method of  claim 5 , wherein one of the plurality of adhesive layers has a curved top surface, a flat bottom surface, and has a thickness decreasing along a direction from center to edge. 
     
     
       8. A package structure, comprising:
 an interposer; 
 a first die and a second die disposed on the interposer; 
 an underfill layer disposed between the first die and the second die, wherein a top surface of the underfill layer substantially levels with a first back-side of the first die and a second back-side of the second die; 
 an adhesive pattern overlying the underfill layer between the first die and the second die; and 
 a thermal interface material (TIM), having a bottom surface in direct contact with the first die, the second die and the adhesive pattern. 
 
     
     
       9. The package structure of  claim 8 , wherein the adhesive pattern comprises a plurality of adhesive layers discretely distributed on the underfill layer between the first die and the second die. 
     
     
       10. The package structure of  claim 9  further comprising an encapsulant laterally encapsulating the first die, the plurality of second dies and the underfill layer, wherein a portion of the plurality of adhesive layers is disposed between the encapsulant and the TIM to separate the encapsulant from the TIM. 
     
     
       11. The package structure of  claim 10 , wherein a sidewall of the encapsulant is substantially aligned with a sidewall of the interposer. 
     
     
       12. The package structure of  claim 9 , wherein each adhesive layer has a bottom surface in direct contact with the underfill layer. 
     
     
       13. The package structure of  claim 9 , wherein one of the plurality of adhesive layers has a curved top surface and a flat bottom surface, and the one of the plurality of adhesive layers has a thickness decreasing along a direction from center to edge. 
     
     
       14. The package structure of  claim 8 , wherein the adhesive pattern laterally extends from a top surface of the underfill layer to cover a portion of the first back-side of the first die and a portion of the second back-side of the second die. 
     
     
       15. The package structure of  claim 8 , wherein the TIM has a plurality of fillers, and the adhesive pattern is free of fillers. 
     
     
       16. The package structure of  claim 1  further comprising:
 a circuit substrate bonded to the interposer; 
 a passive device disposed on the circuit substrate; and 
 a lid adhered to the circuit substrate, the first die, and the second die, wherein the lid covers and surrounds the passive device, the first die and the second die. 
 
     
     
       17. A package structure, comprising:
 an interposer; 
 a first die and a second die disposed on the interposer; 
 an underfill layer disposed between the first die and the second die; 
 a multi-layered structure disposed on the first die, the second die and the underfill layer, wherein the multi-layered structure comprises:
 a pair of metal layers; 
 a thermal interface material (TIM) disposed between the pair of the metal layers; and 
 
 a lid adhered to a top metal layer among the pair of metal layers, wherein the lid covers the first die and the second die. 
 
     
     
       18. The package structure of  claim 17 , wherein the TIM is spaced apart from the lid by the top metal layer among the pair of metal layers. 
     
     
       19. The package structure of  claim 17 , wherein the TIM is spaced apart from the first die and the second die by a bottom metal layer among the pair of metal layers. 
     
     
       20. The package structure of  claim 19 , wherein the top metal layer among the pair of metal layers is spaced apart from the bottom metal layer among the pair of metal layers by the TIM.